Marfan syndrome (MFS) is a common disorder caused by mutations in the gene encoding the matrix protein fibrillin-1. Our prior work has shown that many manifestations of MFS, including aortic aneurysm, valve disease, emphysema and skeletal muscle myopathy, are caused by excessive activation of and signaling by the TGFbeta family of growth factors and can be attenuated by TGFbeta blockade in mouse models. The prevailing view has been that MFS manifests abnormal behaviors of """"""""normal"""""""" cells due to alterafions in their extracellular environment. We now present evidence for """"""""abnormal"""""""" cells within the aortic wall of adult MFS mice that have undergone a TGFbeta-dependent permanent transifion in identity and character during early development due to a process termed endothelial-to-mesenchymal transifion (EnMT). After transifion, resulfing myofibroblasts exhibit many deleterious behaviors including high TGFbeta signaling, angiotensin II (Angll)-dependent fibrosis, and high expression of matrix-degrading enzymes. The major hypotheses to be tested in this work are that EnMT-derived cells drive progression of disease and that EnMT continues to populate the ascending aorta during postnatal life in disease states. Using mouse models, we will determine the pathways that drive EnMT in the aorta of fibrillin-1 deficient mice and will purify EnMT-derived cells, allowing identification of their deleterious behaviors and explorafion of strategies to tame them. Currently, we can envision at least 9 different therapeutic agents that will theoretically prevent ongoing EnMT and/or modulate the nonproducfive performance of myofibroblasts resident within the aortic wall at the time of initiation of treatment. These will be tested in genetically defined and validated mouse models of MFS. Remarkably, a number of these agents are already in clinical use for other indications, suggesting the potential for rapid translafion to people with MFS. Our current data suggest a developmentally-imposed fixed alterafion in cellular idenfity in the prediposition for apparently acquired late-onset phenotypes in MFS, This paradigm represents a novel way of thinking about genefic predisposifion, aids in the elucidation of therapeufic limitafions and opportunities, and will likely prove relevant to other condifions.

Public Health Relevance

This work will explore the basic mechanisms driving aortic aneurysm, a condifion responsible for the death of 1-2% of individuals in industrialized countries. There is high potenfial that this work will derive novel therapeufic strategies for Marfan syndrome, and that these insights will prove relevant to other presentafions of aortic aneurysm.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Program Projects (P01)
Project #
5P01AR049698-10
Application #
8527712
Study Section
Special Emphasis Panel (ZAR1-MLB-F)
Project Start
Project End
2015-08-31
Budget Start
2013-09-01
Budget End
2014-08-31
Support Year
10
Fiscal Year
2013
Total Cost
$465,467
Indirect Cost
$30,817
Name
Icahn School of Medicine at Mount Sinai
Department
Type
DUNS #
078861598
City
New York
State
NY
Country
United States
Zip Code
10029
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